Retroperitoneal fibrosis was first clearly described by Albarran at the beginning of the century as ‘stenosing periureteritis’. In 1902 he practised his operation of libération externe, designed to disengage the ureters from the scar tissue and fibrous masses that surrounded them. In 1948 Ormond described two patients with diffuse fibrosis of the retroperitoneal tissues, and established the clinical and pathological entity of idiopathic retroperitoneal fibrosis more clearly. An increasing number of causes of retroperitoneal fibrosis are now recognized and can be divided into benign and malignant.

Idiopathic retroperitoneal fibrosis, comprising two-thirds of the benign cases, is the best known of the group of fibrosing syndromes which include mediastinal fibrosis and sclerosing cholangitis. A dense plaque of fibrous tissue forms in the lower abdomen and extends laterally and downward from the renal arteries over the promontory of the sacrum, encasing, but not usually infiltrating, the hollow tubes, aorta, inferior vena cava, and ureters (Fig. 1) 1349. The central portion of the plaque consists of dense scar tissue, while the growing margins have the histological appearance of chronic inflammation, with a mixture of mononuclear cells interspersed with occasional giant cells and eosinophils. Idiopathic retroperitoneal fibrosis may occur in areas where the wall of the aorta or other arteries have severe atherosclerosis with damage of the media. When this occurs, insoluble lipid (ceroid) leaks into the periaortic tissue and induces an IgG-mediated immune response. Chronic periaortitis has been suggested as a more appropriate term for this condition (see Section 7.2 34).

Idiopathic retroperitoneal fibrosis normally affects male patients in their fifth or sixth decade of life. One uncommon but well-recognized cause of this condition is the drug methysergide maleate which has been taken for migraine. Occasionally, long-standing urinary tract infections, especially with extravasation, can lead to retroperitoneal fibrosis, although extravasation in the absence of infection seldom leads to fibrosis. Haemorrhage into the retroperitoneal space from a leaking abdominal aortic aneurysm is said to be a cause of this condition, but this seems unlikely, and it is more probable that the association of abdominal aortic aneurysm with idiopathic fibrosis is due to an immune response to insoluble lipid.

The most common malignant tumour presenting as retroperitoneal is a lymphoma, and the diagnosis may be missed at laparotomy if a deep biopsy is not taken. Carcinoma of the breast, stomach, pancreas, colon, renal tract, and prostate, and carcinoid tumours may be associated with retroperitoneal fibrosis due to metastases. It may be difficult to identify the underlying metastatic tumour.

Radiotherapy in the treatment of cancer can also cause retroperitoneal fibrosis, although this is much less common today with more precise field localization before radiotherapy. Chemotherapy, especially following treatment of testicular tumours, may leave fibrous retroperitoneal masses which can involve the ureter. These may or may not contain residual tumour, and may require surgical removal.

The clinical picture may be associated with an underlying cause, such as an abdominal aortic aneurysm, or may be relatively non-specific and include loss of appetite and weight, fever, sweating, and malaise. Hypertension may be present in up to 60 per cent of cases, and pyuria is a common finding. A girdle distribution of pain in the abdomen may be described. Classically the erythrocyte sedimentation rate is high. The major complication of retroperitoneal fibrosis is ureteric obstruction which, if bilateral, can lead to anuria and renal failure.

If the patient is unwell due to renal failure, the obstruction can be relieved by double J stents, passed in either an antegrade or retrograde fashion, or nephrostomies if unsuccessful. In this situation it is important to watch for and correct the loss due to diuresis after relief of the obstruction. Once the immediate urgency of the situation has been resolved, there is time to find the underlying cause.

The classic appearance on the intravenous urogram or antegrade pyelogram is that of medical displacement of the ureters with dilatation of the ureter and pelvis above (Fig. 2) 1350. Ultrasound examination may demonstrate the fibrous plaque as an echo-free mass with smooth borders, thickest at the sacral promontory. Both computerized tomography scanning and magnetic resonance imaging can define the area of fibrosis precisely (Fig. 3) 1351. Fine-needle biopsy of the mass may be helpful in confirming the presence of malignant disease, but a negative result does not exclude malignancy.

The role of steroids remains a subject of debate. They may decrease the oedema often associated with retroperitoneal fibrosis and in this way help in resolution of the obstruction. If they are used, it is probably wise to terminate the steroids when the erythrocyte sedimentation rate returns to normal. Spontaneous resolution of retroperitoneal fibrosis in the absence of treatment is known to occur.

Laparotomy is often necessary to free the ureters from the encasing fibrous tissue. At the same time, biopsies should be taken to exclude an underlying malignant process. It is essential that large deep biopsies are taken for this purpose as it is very difficult to exclude malignancy with small, superficial biopsies. In patients who are unwell, or have one non-functioning kidney, it may be better to operate on only one side rather than both.

In the presence of renal dysfunction, ureterolysis is performed. With care, a plane can usually be found between the ureters and fibrous tissue. It is often easier to begin just above the bladder, as the ureter is usually free at this point and, as the plaque is entered, a plane can be found between the ureter and the plaque. It is often helpful to place a sling around the ureter, and insert a right-angle forceps between the plaque and the ureter, and then cut down on to the forceps with a scalpel. The insertion of a stent or ureteric catheter up the ureter helps to identify it. Great care must be taken on the right-hand side to avoid damage to the inferior vena cava, which is often very difficult to identify in the inflammatory fibrotic mass of tissue.

After freeing the ureters from the fibrous sheath which surrounds them, omentum can be mobilized and used to wrap the ureters throughout their length, thus keeping them free of fibrous tissue (Fig. 4) 1352. In mobilizing the omentum, it must be remembered that the blood supply runs vertically down the gastroepiploic arch, and the majority of the blood to the arch comes from the right side. While wrapping the ureters in omentum does not guarantee freedom from recurrent obstruction, it seems to be better than other techniques.

Rarely, dense fibrosis is restricted to the lower ureters, and it is possible to reimplant a normal ureter into the bladder with a psoas hitch or Boari flap. Occasionally, long strictures form after the initial ureterolysis, and these may have to be treated by more specialized techniques, such as renal autotransplantation.

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